SendEmailMessage example

if (null !== $this->envelope) {
            $message->envelope($this->envelope);
        }

        if (null !== $transportName) {
            $message->transport($transportName);
        }

        if (null === $this->bus) {
            $this->transport->send($message->getMessage(), $message->getEnvelope());
        } else {
            $this->bus->dispatch(new SendEmailMessage($message->getMessage(), $message->getEnvelope()));
        }
    }

    public function supports(Notification $notification, RecipientInterface $recipient): bool
    {
        return $recipient instanceof EmailRecipientInterface;
    }
}

$clonedEnvelope = null !== $envelope ? clone $envelope : Envelope::create($clonedMessage);
            $event = new MessageEvent($clonedMessage, $clonedEnvelope, (string) $this->transport, true);
            $this->dispatcher->dispatch($event);
            $stamps = $event->getStamps();

            if ($event->isRejected()) {
                return;
            }
        }

        try {
            $this->bus->dispatch(new SendEmailMessage($message, $envelope), $stamps);
        } catch (HandlerFailedException $e) {
            foreach ($e->getNestedExceptions() as $nested) {
                if ($nested instanceof TransportExceptionInterface) {
                    throw $nested;
                }
            }
            throw $e;
        }
    }
}